Personal computer systems always include means for initializing the computer when the power is turned on. Ordinarily, the booting sequence includes various tests of computer components to determine whether everything connected in the system is in operating order. Ultimately, a screen is presented to the computer user to enable interaction through which commands can be received.
It is common for initialization routines to include bringing up an operating system such as, for example, the IBM Disk Operating System (DOS) so that upon turning on the computer the system initialization includes loading DOS and eventually providing a "DOS prompt" on the screen for interaction. Typically, the user will have selected the operating system to be used such as IBM DOS and will have placed a diskette containing the DOS into a diskette drive so that the boot-up procedure can include loading DOS. If desired, the user may have copied the operating system onto a fixed disk associated with the system so that the diskette need not be inserted every time the computer is turned on.
Once a computer has been initialized and an operating system such as IBM DOS is resident, application programs which run under the operating system can be used. For example, word processors which operate under the operating system can be utilized, spreadsheet programs can be utilized, and information applications such as stock quotations or educational services or User's Club can be run. Should, however the user desire to run an application under a different operating system, it is typically necessary to turn the computer off, insert a different operating system in the diskette drive, turn the computer back on and initialize the computer in the different operating system. Then the application can be inserted in the diskette drive and the application can finally be run.
In order to save time for the user, a personal computer has been developed with the IBM DOS operating system located in read-only-memory (ROM) so that initialization of the machine directly brings the machine up with that operating system ready to use, thus avoiding the need for the computer user to insert a diskette containing an operating system into the diskette drive and/or also avoiding the need for the computer to turn to the fixed disk to find an operating system. However, many users may desire to bring up the machine with a different operating system from that particular version of IBM DOS located in ROM. Therefore, a flexible initialization system has been invented to bypass the operating system located in ROM and thereby enable the user to bring the computer up in an operating system of choice. Additionally, the flexible initialization system enables the user to bring the computer up already in a particular application. Also, provision is made to allow the reading of special DOS start-up files which alter the start-up which would occur utilizing the entirety of the DOS located in ROM. In that manner, flexibility is provided the user so that initialization results in a customized starting point of the user's choice.
It is an object of this invention to provide a computing system which enables the computer user to automatically start the computer in an operating system located in ROM or in the operating system of choice, and then go to a different operating system without turning the computer off and back on.
It is a further object of this invention to enable the computer user to retain the chosen customized initialization for use on the next power-on sequence.